1. Field of the Invention
Apparatuses and methods consistent with the present invention relate to encoding/decoding stereo audio, and more particularly, to parametrically encoding/decoding stereo audio by minimizing the number of parameters needed for the encoding/decoding of stereo audio.
2. Description of the Related Art
In general, a method of encoding multichannel audio includes waveform audio coding and parametric audio coding. The waveform encoding includes MPEG-2 MC audio coding, AAC MC audio coding, and BSAC/AVS MC audio coding.
In the parametric audio coding, an audio signal is encoded by dividing the audio signal into components such as frequency or amplitude and parameterizing information on the frequency or amplitude. For example, when stereo audio is encoded using the parametric audio coding, left channel audio and right channel audio are downmixed to generate mono audio and the generated mono audio is encoded. Then, parameters about interchannel intensity difference (IID), interchannel correlation (ICC), overall phase difference (OPD), and interchannel phase difference (IPD) needed for restoring the mono audio to stereo audio are encoded.
The parameters on the interchannel intensity difference and the interchannel correlation are encoded as information for determining the intensity of the left channel audio and the right channel audio. The parameters on the overall phase difference and the interchannel phase difference are encoded as information for determining the phase of the left channel audio and the right channel audio.
Many studies have been made on a method of efficiently encoding mono audio so that the mono audio may be encoded at a high compression rate. However, to efficiently encode stereo audio, not only the mono audio but also the above-described parameters of stereo audio need to be efficiently compressed and encoded.